JPS61123060A - Detecting device of number of revolutions for belt drive player - Google Patents

Abstract

PURPOSE:To obtain a rotation detecting device of high quality for belt drive player, by using a belt which has transmission rate and reflection rates which change periodically, and also providing photo-interrupter which detects transmission rate and reflection rate of the belt. CONSTITUTION:A belt 2 is composed of rubber which has high transmittivity and reflection, on the outside surface of which black painted lines 8 is painted so that it intersects the transmission and reflection periodically. The rotation of a motor 1 is conveyed by a belt 2 which is hooked to a rib 4 and capstan 5 to a turntable 3. And by providing a photo-interrupter 9 to detect the transmission and reflection of the belt, the number of revolutions of the belt drive player is detected with high accuracy by small number of composing parts.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for detecting the rotational speed of a belt drive player.

Conventional technology In recent years, many belt drive players have been used, which detect the rotational speed of the turntable, or a frequency proportional to the rotational speed, and control the speed so that the frequency remains constant, improving the accuracy of the rotational speed. It is being

A conventional rotation speed detection device for a belt drive player will be described below.

FIG. 3 is a block diagram of a conventional rotation speed detection device for a belt drive player, and FIG. 4 is a partially enlarged view thereof.

1 is a motor, 2 is a belt, 3 is a turntable, 4 is a rib on a cylinder on which the belt is attached to the turntable 3, 6 is a capstan fixed to the shaft of the motor 1, 6
7 is a disc-shaped magnet fixed to the shaft of the motor 1 and magnetized with multiple poles in the circumferential direction, and 7 is a magnetic resistance element provided circumferentially opposite to the magnet 6.

The operation of the belt drive player rotation speed detection device configured as above will be described below.

The rotation of the motor 1 is transmitted to the turntable 3 by a belt 2 that is wrapped around a rib 4 and a capstan. At this time, the rotation speed of turntable 3 is RC times/second]
Then, the rotation speed of the motor 1 is D, R(
times/second]. At this time, if the number of magnetized poles of the magnet 6 is N, then it is 31.

A magnetic flux change of D-R-N [times/second] is applied to the magnetoresistive element 7, and a frequency of D-R-N (Hz) is generated as an output. In other words, a frequency output proportional to the rotation speed of the turntable can be obtained.

Problems to be Solved by the Invention However, the conventional configuration described above requires a magnet 6 and a magnetic resistance element 7 for detecting the number of revolutions, so there are many components, and in order to improve the accuracy of detecting the number of revolutions, When the number of magnetized poles of the magnet 60 is increased, the magnetic flux of the magnet 6 decreases, resulting in a problem that the frequency detection output decreases.

The present invention solves the above-mentioned conventional problems, and aims to provide a high-precision rotation speed detection device for a belt drive player with a simple configuration.

Means for Solving the Problems The present invention provides a belt drive player comprising a belt whose light transmittance or reflectance changes periodically, and a photocoupler which detects the light transmittance or reflectance of the belt. This is a rotation speed detection device.

According to the present invention, by detecting changes in light transmitted through or reflected from the belt, a highly accurate frequency output proportional to the rotational speed of the belt drive player can be obtained.

Embodiment FIG. 1 is a partially enlarged view of a rotation speed detection device for a belt drive player in an embodiment of the present invention, and FIG. 2 is a plan configuration diagram.

In FIGS. 1 and 2, motor 1. Turntable 3. Reply 4. The configuration is exactly the same as that of the conventional example with six capstans. Reference numeral 2 denotes a belt, and black painted lines 8 are periodically formed on the outer peripheral surface of the rubber belt, which has a high degree of light transmission or reflection, so as to prevent transmission or reflection of light. 9 is a photo interrupter.

The operation of the belt drive player rotation speed detection device of this embodiment configured as described above will be described below. The rotation of the motor 1 is transmitted to the vane return table 3 by a belt 2 that is wrapped around a lip 4 and a capstan 6.

The rotation speed of turntable 3 at this time is RIEII/f+
Then, the moving speed of the belt 2 is R·2πr (m/S), where r is the radius of the lip 4.

Therefore, if the number of 1 mp painted lines 8 on the belt 2 is n, the frequency of change in light transmittance detected by the photointerrupter 9 per second is R・2πr・nCHz), and the output of the photointerrupter 9 is , R・2πr-nCH
z) frequency can be obtained. When detecting the reflection of light, a photo sensor is used instead of a photo interrupter.

As described above, according to this embodiment, by obtaining the periodic signal directly from the belt 2 of the belt drive player, the number of components can be reduced. In addition, in terms of output frequency, the conventional example suffers from a decrease in magnetic flux density due to an increase in the number of magnetized magnetic poles.
Although it was difficult to obtain a high frequency, in this example,
Even if the number of black painted lines 8 on the belt 2 is increased, the light transmittance or reflectance itself does not change, so the upper limit of the 6Bage frequency is determined only by the response speed of the photointerrupter (or photosensor) 9. Therefore, it is possible to obtain a high frequency without reducing the output compared to the conventional example.

In this embodiment, the light transmittance or reflectance of the belt 2 is changed using the black painted line 8, but it may be a painted line of another color that blocks or absorbs light. It may also be printed on paper.

Effects of the Invention The present invention provides a belt drive with fewer components by providing a belt whose light transmittance or reflectance changes periodically and a photo coupler which detects the light transmittance or reflectance of the belt. The rotation speed of the player can be detected with high accuracy.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged view of a rotation speed detection device for a belt drive player according to an embodiment of the present invention, FIG. 2 is a plan configuration diagram of the same embodiment, and FIG. 3 is a conventional rotation speed detection device for a belt drive player. FIG. 4 is a partially enlarged view of FIG. 3. 7t\-2 1...Motor, 2...Belt, 3...Turntable, 5...Capsta 7.8...Black painted line, 9---Photo interrupter. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] A rotation speed detection device for a belt drive player, comprising a belt whose light transmittance or reflectance changes synchronously, and a photocoupler which detects a change in the transmittance or reflectance of the belt.